Dynamic buffer allocation in similar infrastructures

ABSTRACT

A method, computer program product, and system includes a processor(s) obtaining historical data related to buffer space usage of a common shared storage resource by a group of j ournals. The processor(s) monitors each journal over repeating temporal periods and determined a predictability for each journal (i.e., predictable or unpredictable. The processor(s) generates usage statics for each journal during each monitored period dependent on whether the journal was predictable or unpredictable during the monitored period. For each monitored period, the processor(s) ranks predictable journals by a buffer space requirement for each journal of the predictable journals. Based on the rankings, the processor(s) determined a buffer space requirement for each journal for a current period, where the current period shares temporal qualities with the given monitored period. The processor(s) allocates, for use during the current period, based on the buffer space requirement, buffer space to each journal.

BACKGROUND

In messaging systems with multiple producers and multiple consumers,producers publish the messages under a topic, for the consumers. Themessaging system maintains multiple topics and the messages in thesetopics are partitioned and stored in persistent data structures calledjournals with one-to-one correspondence between a given journal and agiven consumer. These journals are maintained in a shared disk storage.

SUMMARY

Shortcomings of the prior art are overcome and additional advantages areprovided through the provision of a method for allocating shared bufferspace to journals in a messaging system. The method includes, forinstance: obtaining, by one or more processors, historical data relatedto buffer space usage for each journal in a group of journals comprisinga messaging system, wherein each journal utilizes buffer spacecomprising a common shared storage resource, by monitoring activity ineach journal over repeating temporal periods; determining, by the one ormore processors, for each journal, based on the obtained historicaldata, a predictability for each journal for each monitored period of therepeating temporal periods, wherein the predictability is selected fromthe group consisting of: predictable and unpredictable, wherein apredictable journal, for a monitored period, uses a predictable amountof buffer space during the monitored period, and an unpredictablejournal, for the monitored period, uses an unpredictable amount ofbuffer space during the monitored period; generating, by the one or moreprocessors, based on the historical data, usage statics for each journalduring each monitored period, wherein the usage statistics generated foreach monitored period are dependent on whether the journal waspredictable or unpredictable during the monitored period; for eachmonitored period, ranking, by the one or more processors, predictablejournals for the monitored period, by a buffer space requirement foreach journal of the predictable journals; based on the rankings for agiven monitored period, determining, by the one or more processors, abuffer space requirement for each journal of the group of journals for acurrent period, wherein the current period shares one or more temporalqualities with the given monitored period; and based on the determining,allocating, by the one or more processors, for use during the currentperiod, based on the buffer space requirement for each journal, bufferspace to each journal of the group of journals, from the buffer space inthe common shared storage resource.

Shortcomings of the prior art are overcome and additional advantages areprovided through the provision of a computer program product forallocating shared buffer space to journals in a messaging system. Thecomputer program product comprises a storage medium readable by aprocessing circuit and storing instructions for execution by theprocessing circuit for performing a method. The method includes, forinstance: obtaining, by one or more processors, historical data relatedto buffer space usage for each journal in a group of journals comprisinga messaging system, wherein each journal utilizes buffer spacecomprising a common shared storage resource, by monitoring activity ineach journal over repeating temporal periods; determining, by the one ormore processors, for each journal, based on the obtained historicaldata, a predictability for each journal for each monitored period of therepeating temporal periods, wherein the predictability is selected fromthe group consisting of: predictable and unpredictable, wherein apredictable journal, for a monitored period, uses a predictable amountof buffer space during the monitored period, and an unpredictablejournal, for the monitored period, uses an unpredictable amount ofbuffer space during the monitored period; generating, by the one or moreprocessors, based on the historical data, usage statics for each journalduring each monitored period, wherein the usage statistics generated foreach monitored period are dependent on whether the journal waspredictable or unpredictable during the monitored period; for eachmonitored period, ranking, by the one or more processors, predictablejournals for the monitored period, by a buffer space requirement foreach journal of the predictable journals; based on the rankings for agiven monitored period, determining, by the one or more processors, abuffer space requirement for each journal of the group of journals for acurrent period, wherein the current period shares one or more temporalqualities with the given monitored period; and based on the determining,allocating, by the one or more processors, for use during the currentperiod, based on the buffer space requirement for each journal, bufferspace to each journal of the group of journals, from the buffer space inthe common shared storage resource.

Methods and systems relating to one or more aspects are also describedand claimed herein. Further, services relating to one or more aspectsare also described and may be claimed herein.

Additional features are realized through the techniques describedherein. Other embodiments and aspects are described in detail herein andare considered a part of the claimed aspects.

BRIEF DESCRIPTION OF THE DRAWINGS

One or more aspects are particularly pointed out and distinctly claimedas examples in the claims at the conclusion of the specification. Theforegoing and objects, features, and advantages of one or more aspectsare apparent from the following detailed description taken inconjunction with the accompanying drawings in which:

FIG. 1 is an illustration of various aspects of a technical environmentin which aspects of embodiments of the present invention may beimplemented;

FIG. 2 (consisting of FIGS. 2A-2B) is a workflow illustrating certainaspects of an embodiment of the present invention;

FIGS. 3A-3C represent examples of hourly usage patterns for variousjournals, as monitored and determined by the one or more programs insome embodiments of the present invention;

FIG. 4 is a workflow illustrating certain aspects of an embodiment ofthe present invention;

FIG. 5 is a workflow illustrating certain aspects of an embodiment ofthe present invention;

FIG. 6 is a workflow illustrating certain aspects of an embodiment ofthe present invention;

FIG. 7 is a workflow illustrating certain aspects of an embodiment ofthe present invention;

FIG. 8 depicts one embodiment of a computing node that can be utilizedin a cloud computing environment;

FIG. 9 depicts a cloud computing environment according to an embodimentof the present invention; and

FIG. 10 depicts abstraction model layers according to an embodiment ofthe present invention.

DETAILED DESCRIPTION

The accompanying figures, in which like reference numerals refer toidentical or functionally similar elements throughout the separate viewsand which are incorporated in and form a part of the specification,further illustrate the present invention and, together with the detaileddescription of the invention, serve to explain the principles of thepresent invention. As understood by one of skill in the art, theaccompanying figures are provided for ease of understanding andillustrate aspects of certain embodiments of the present invention. Theinvention is not limited to the embodiments depicted in the figures.

As understood by one of skill in the art, program code, as referred tothroughout this application, includes both software and hardware. Forexample, program code in certain embodiments of the present inventionincludes fixed function hardware, while other embodiments utilized asoftware-based implementation of the functionality described. Certainembodiments combine both types of program code. One example of programcode, also referred to as one or more programs, is depicted in FIG. 8 asprogram/utility 40, having a set (at least one) of program modules 42,may be stored in memory 28.

In current messaging systems with multiple producers and multipleconsumers, producers publish the messages under a topic for theconsumers, while the messaging system maintains multiple topics. One ormore programs executed by at least one processing resource in thesesystems partition and store the topics in journals, which are persistentdata structures and are maintained in a shared disk storage. In thesecurrent systems, it is the job on an administrator to manually allocatea certain buffer space to each journal (to store the messages) untilthat allocated buffer space is consumed. To prevent buffer overflow, theadministrator tracks of the usage patterns of the messaging system andits underlying journals and manually adjusts the buffer size for eachjournal, based on estimated producer and/or consumer behavior. Becausethe administrator will distribute all available disk storage space toallocate to the journals, an individual journal cannot release un-used(but previously allocated) storage to a common pool. To preventavailable disk storage space from being underutilized throughover-allocation to certain journals, based on assumptions that provefalse, one or more programs monitor buffer consumption for all thejournals constantly and based on data gathered through the monitoring,the administrator continuously adjusts and updates buffer sizesmanually. These existing systems result in both a reactive and a manualprocess. Because these current systems require manual intervention, theallocation process can be both time-consuming as well as error prone.

Multiple producers/publishers share same infrastructure, but thebehavior of consumers/subscribers may differ. An example of a messagingsystem that would benefit from the implementation of certain aspects ofthe present invention is a public logging and monitoring service, whichincludes a queue of events and messages. FIG. 1 depicts a technicalarchitecture 100 of this public logging and monitoring service, whichincludes shared disk storage 110 utilized as buffers 130 a-c (includingBuffer A 130 a, Buffer B 130 b, and Buffer C 130 c) by producers 120 a-c(including Producer A 120 a, Producer B 120 b, and Producer C 120 c). Inthis technical environment 100, one or more programs executing on atleast one processor queue the logs and monitor various metrics. Theconsumption rate of the logs and monitoring messages may vary dependingupon the capacity of log processing and message monitoring processingcapabilities. The common architecture 100, including the shared diskstorage 110 is shared by the services producing logs, and thoseproducing metrics; these programs may share common buffers or sharebuffers that share the same storage mechanisms. The producers publishmessages by topic 140 and one or more programs partition topics andstore topics in one or more journals, to which the consumers 150 a-b(including Consumer 1 150 a and Consumer 2 150 b) may subscribe.

Some existing systems attempt to remedy issues introduced by manuallyadjusting buffers by providing one or more programs to adjust buffersizes automatically, based on historical data. Unfortunately, theseapproaches also fall short in efficiency and can lead to incorrectallocations, such that certain journals remove unused resources from thepool of available shared resources. The shortcomings of these systemsare the result of the one or more programs failing to consider that thesize of a journal may be unpredictable, in the demand for buffer space,for example, due to variations in message production and consumptionpatterns. In these existing systems, one or more programs monitor thebuffer space usage of each journal to collect historical data. The oneor more programs then analyze the historical data to build a predictionmodel for the buffer space used by each journal (e.g., as a function oftime and the ratio of rate of consumption and rate of production). Theone or more programs then automatically allocate buffer space for eachjournal, based on the prediction model generated, but because thesemodels do not take into account of the unpredictability in the demandfor buffer space (e.g., based on variations in the message productionand consumption patterns for certain journals at certain times), spacecan be automatically allocated that is not required by a journal,leading to inefficiencies in the allocation of this (finite) sharedspace (e.g., FIG. 1, 110).

In contrast to the existing approaches described, in embodiments of thepresent invention, a computer-implemented method, a computer programproduct, and a computer system include program code that: 1) monitorsthe buffer space usage (i.e., buffer usage pattern) of each producerand/or publisher utilizing a messaging system by collecting historicaldata at regular intervals, including but not limited to, each hour of aday, each day of a week, and/or each day of a month; 2) ranks and/oradjusts earlier established rankings of the producers and/or publishersperiodically; and 3) dynamically adjusts and/or readjusts the buffersizes allocated based on the rank and/or change in rank for eachproducer and/or publisher. Regarding this ranking aspect, in variousembodiments of the present invention, one or more programs rankpublishers based on the buffer usage and time slice based analysis. Thisranking is a continuous process such that the one or more programs mayconstantly (and/or intermittently) readjust buffer size based on thistime slice based analysis. Additionally, unlike certain existing bufferallocation approaches, embodiments of the present invention may beutilized to specifically address buffer allocations where multipleproducers share the same underlying infrastructure for buffer space.

Aspects of various embodiments of the present invention provide variousadvantages over shared resource allocation systems and methods utilizedby existing messaging systems. As will be discussed in greater detailherein, one or more programs in some embodiments of the presentinvention provide the following advantages/functionalities: 1)efficiency in resource allocation where no seasonality or patterns ofusage exist to provide guidance; 2) efficiency in resource allocationwhere historical usage data indicates a mix of both predictable andunpredictable usage patterns; 3) dynamic buffer allocation based on acombination of predicted values and current usage values, to determinethe best corrective action to optimize allocation efficiency, includingtaking corrective allocation actions, if predicted and actual usagebehavior for all topics are synchronized, and localizing correctiveactions when there is a deviation in a predicted and an actual usagebehavior, in order to affect certain topics, only; and 4) dynamicthresholding for both predictable and unpredictable usage patterns.

Aspects of embodiments of the present invention represent improvementsto existing computing technology and are inextricably tied to computing.For example, embodiments of the present invention dynamically allocatememory resources, including buffer sizes, to physical and virtualresources sharing (finite) memory resources of a computing environment.Embodiments of the present invention also rank publishers based on thebuffer usage and time slice based analysis. Additionally, embodiments ofthe present invention address an issue inextricably tied to computingand provide a novel approach to this known issue: resource allocationinefficiencies based on either faulty and/or user-intensive manualallocations, or automated allocations that rely on historical data thatfails to account for usage patterns (or lack of usage patterns) thatgreatly impact allocation efficiency. Space allocation in existingsystems is not only inefficient, it can also lead to data loss, which isprevented by the dynamic approach provided herein. Because existingsystems are unable to dynamically adjust the buffer allocation toproducers by analyzing the consumption nature of correspondingconsumers, data loss occurs as buffers utilized by certain producers hitan allocation ceiling, while others have plenty of storage space.

FIG. 2 (comprised of FIGS. 2A-2B) is a workflow 200 that illustratescertain aspects of some embodiments of the present invention. Asaforementioned, a given messaging system is utilized by one or more(generally, multiple) producers and one or more (generally, multiple)consumers. The producers publish messages by topic and one or moreprograms executing on at least one processing circuit, that comprisesthe messaging system, partitions the topics and stores them in one ormore journals. Journals are persistent data structures within and/oraccessible to one or more computing nodes that comprise the messagingsystem. The one or more programs of the messaging system distributeshared disk storage, including allocating space to the one or morejournals. Specifically, the one or more programs allocate buffer spaceto the messages by adjusting the buffer size of the one or morejournals.

As will be discussed in greater detail, the workflow 200 of FIG. 2 takesinto account certain realities regarding a messaging system toefficiently manage buffer sizes of a finite shared storage resource.First, in embodiments of the present invention, one or more programsallocate buffer sizes in a manner that is inversely proportional to aratio of consumption rate to production rate, because the behavior ofthe producers and the behavior of the consumers affects buffer usage,which the one or more programs utilize to determine buffer-sizeallocation. Second, one or more programs allocate buffer sizes andre-allocate buffer sizes based on temporal patterns of journal usage,including but not limited to, seasonal behaviors, behaviors associatedwith particular hours of days, behaviors associated with days of weeks,and/or behaviors associated with days of months. Third, the one or moreprograms allocate buffer sizes based on observations that producersand/or consumers may deviate from a given established seasonal usagepattern. Based on these realities, one or more programs in embodimentsof the present invention analyze historical buffer usage data toidentify time windows (e.g., hourly) when a given journal has either apredictable (e.g., knowable) or an unpredictable (e.g., unknowable)usage pattern.

Referring to FIG. 2, in some embodiments of the present invention, oneor more programs executed by at least one processing circuit monitorbuffer usage of each journal in a messaging system (210). As part of themonitoring, the one or more programs collect historical data in eachjournal for repeating temporal periods (220). For example, in someembodiments of the present invention, the one or more programs monitorand collect data for each hour of a day, for each day of a week, and/orfor each day of the month. This historical data can be usage data. Bybasing monitoring and collection on consistent temporal periods, one ormore programs in embodiments of the present invention can identify theexistence or absence of usage patterns for each journal within thedefined temporal periods. These temporal periods may also be understoodas time windows or time slices.

In embodiments of the present invention, the one or more programsanalyze the collected data to determine if a journal has predictable orunpredictable usage for each period of the repeating temporal periods(230). The one or more programs compute usage statistics for thejournals reflecting the usage in each period of the repeating temporalperiods (240). As part of this computation, the one or more programsdetermine if each journal is predictable or unpredictable for eachperiod of the repeating temporal periods (241). For the journals thatthe one or more programs determine to be predictable, the one or moreprograms compute a full set of usage statistics for these journals forthe periods (242). Also as part of the computation, for journals thatthe one or more programs determine to be unpredictable (i.e., haveunpredictable usage in a given temporal period), the one or moreprograms compute, for the temporal period, an abbreviated set of usagestatistics for these journals (244). For example, in some embodiments ofthe present invention, for predictable journals, the one or moreprograms determine the minimum usage, maximum usage, average usage, andstandard deviation, for the journals for each hour during a day. Forunpredictable journals, the one or more programs may determine anaverage predicted buffer usage and a standard deviation from thisaverage. The one or more programs store the historical data as well asthe journal designations (e.g., predictable, unpredictable) on a memoryresource accessible to the one or more processors (248).

FIGS. 3A-3C represent examples of hourly usage patterns for journals A,B, and C, as monitored and determined by the one or more programs insome embodiments of the present invention. As illustrated in FIGS.3A-3C, for different time slices (temporal periods) the one or moreprograms determine that the usage patterns for a given journal may bepredictable or unpredictable. FIG. 3A is related to Journal A, FIG. 3Bto Journal B, and FIG. 3C to Journal C.

Referring to FIG. 3A, which provides data related to usage of Journal Aduring different temporal periods, the one or more programs determinedthat the journal's usage was unpredictable for five time slices orwindows. For the remainder of the periods, the one or more programsdetermined that the journal was predictable. As depicted in FIG. 2, theone or more programs computed usage statistics including minimum,maximum, average, and standard deviation, for the periods where JournalA was predictable (242) and usage statistics including only average andstandard deviation, for Journal A for periods that the one or moreprograms determined that the usage was unpredictable (244). FIG. 3Bprovides the same usage statistics for Journal B and FIG. 3C providesthese computed values for Journal C.

Returning to FIG. 2, based on the computed usage, for the relevanttemporal period for which the one or more programs determine whethereach journal was predictable or unpredictable (e.g., hour-of-day,day-of-week, and/or day-of-month), the one or more programs rank thepredictable journals for each period based on buffer usage levels (250).The rankings result in a per-temporal period ranking index for eachjournal. In embodiments of the present invention, the one or moreprograms utilize machine learning application programming interfaces(APIs) in order to generate the rankings. In embodiments of the presentinvention, certain of the APIs may be part of a known cognitive agent,such as the IBM Watson® Application Program Interface (API), a productof International Business Machines Corporation. IBM Watson® is aregistered trademark of International Business Machines Corporation,Armonk, N.Y., US. In some embodiments of the present invention, APIsutilized by the one or more programs may include, but are not limitedto, Retrieve and Rank (i.e., a service available through the IBM Watson®Developer Cloud that can surface the most relevant information from acollection of documents), concepts/visual insights, trade off analytics,document conversion, and/or relationship extraction.

The one or more programs determine (and determine anew) a buffer spacerequirement for each journal as each period of the temporal periodsutilized for the rankings elapses (260). To make this determination, foreach temporal period (i.e., time window or time slice, e.g., each hour)the one or more programs utilize the rankings to determine a bufferspace requirement for each journal. For each temporal period, the one ormore programs determine a buffer size threshold for each journal, basedon the predictability, which is based on the analysis of the historicaldata (264). The one or more programs may utilize the thresholddeterminations to detect or predict a service level (SLA) breach. Foreach temporal period, the one or more programs determine what portion ofallocated buffers may be reclaimed for allocating to unpredictablejournals (266). The portion of the buffers that can be reclaimed referto portions of the buffer that had been previously allocated to apredictable journal, which are not going to be needed, based on thepredictions, and can therefore be re-allocated. The one or more programsmay reclaim these portions for use by the unpredictable journals becausethe future space requirements of these journals cannot be determined bythe one or more programs, based on the historical data. For eachtemporal period, for each journal, the one or more programs set thebuffer size and set the threshold buffer size (268).

Returning to the example journals in FIGS. 3A-3C, and using an hour asan example of a temporal period, the one or more programs rank (e.g.,FIG. 2, 250) the journals by ranking the predictable journals indecreasing order of usage pattern for a given hour, excluding theunpredictable journals, from the rankings. At each hour, based on theranking for that hour of the day, the one or more programs determine thebuffer space requirement for each journal (e.g., FIG. 2, 260). Asillustrated in FIGS. 3A-3C, for the predictable journals, or, rather,the journals that are predictable during a relevant time period, forthat time period (e.g., an hour), the one or more program determine thebuffer space requirements by utilizing the minimum and maximum bufferusage values. Upon determining the space requirements for thepredictable journals, the one or more programs redistribute theremaining buffer space to the journals previously determined to beunpredictable during the time period by utilizing the hour-of-dayaverage predicted buffer usage values, as illustrated in FIGS. 3A-3C.For example, the one or more programs may weigh the day of-week,day-of-month ranking, and average predicted buffer usage to determinethe allocated buffer-size for the unpredictable journals. In the eventthat the one or more programs determined that all the journals werepredictable for a given hour (the temporal period utilized in thisexample), the one or more programs reserve any unallocated buffer spacein a pool that the one or more programs may reclaim if/when a journalbecomes unpredictable.

Per FIG. 3A, the one or more programs determined that Journal A ispredictable for hour 00:00-01:00. An example of an allocated buffer sizefor Journal A, for that time, based on the maximum usage can be 6 units(100% of 6). Per FIGS. 3B and 3C, in the same time period, in the sametime period, hour 00:00-01:00, the one or more programs determined thatJournal B (see FIG. 3B) and Journal C (see FIG. 3C) are unpredictable.If the total shared space is 20 units, after the allocation to JournalA, the remaining space is 14 units. Thus, the one or more programsdetermine how to allocate the remaining 14 units of space betweenJournal B and Journal C. Referencing the collected and computed data,the one or more programs determine that the ratio of the average bufferspace of Journal B to Journal C is 2:4. The average space for therelevant time period for Journal B is 2 units (see FIG. 3B) and theaverage space for the time period for Journal C is 4 units (see FIG.3C). Thus, the one or more programs determine the allocation for JournalB by multiplying the average allocation for Journal B during therelevant time by the available buffer space and divide that result bythe space allocated to Journal A, allocating 4.3 units to Journal B(i.e., 2*14/6=4.3). The one or more programs determine how much bufferspace to allocate to Journal C by multiplying the average allocation forJournal C during the relevant time by the available buffer space anddivide that result by the space allocated to Journal A, allocating 9.3units (i.e., 4*14/6=9.3).

As illustrated in FIG. 2, based on identifying the pattern in the timewindow, the one or more programs may continuously, as well asperiodically, reallocate the buffer sizes of the journals, for usageperiods in which the usage of journals is predictable or unpredictable.The one or more programs determine the buffer usage (e.g., minimum,maximum, average, and/or a standard deviation) for time-windows andutilize this information to allocate the buffer sizes of journals,dynamically. The one or more programs allocate buffer space to journalsfor time windows in which the one or more programs determine thatutilization of these journals is predictable (e.g., hourly) andre-distribute the remaining buffer space of the shared storage tojournals that the one or more programs for which the one or moreprograms have determined that the utilization for the time windows isunpredictable. In embodiments of the present invention, the one or moreprograms determine whether usage is predictable or unpredictable for agiven journal during a given time window by analyzing average usageextracted from the historical data.

As illustrated in FIG. 2, for each temporal period, the one or moreprograms determine a buffer size threshold for each journal based on thepredictability, which is based on the analysis of the historical datawhich one or more programs may utilize the threshold determinations todetect or predict a service level (SLA) breach (268). Referring to theexample journals, Journal A, Journal B, and Journal C, at each hour, theone or more programs determine the buffer-size thresholds, based on thepredictability. In some embodiments of the present invention, if the oneor more programs determine that the buffer size is predictable for thejournal, then the one or more programs set the buffer size threshold as90% of the maximum value. If the one or more programs determine that thebuffer size is unpredictable, then the one or more programs set thebuffer-size threshold as a function of average predicted buffer usageand the standard deviation from the predicted buffer usage.

Referring to FIG. 3A, the one or more programs can determine a bufferside threshold for Journal A, for a given temporal period. For thepredictable hour of 00:00-01:00, the one or more programs may determinethat the buffer size threshold is 90% of the maximum value is, 6 units(i.e., 90% of 6). For the unpredictable hour of 05:00-06:00, because theaverage is 7 units, and the standard deviation (σ) 2 units, the one ormore programs may determine the buffer size threshold as 7+3*2,calculated using the average +3*σ.

Returning to FIG. 2, for each temporal period, the one or more programsdetermine what portion of the buffers may be reclaimed for unpredictablejournals (266). In some embodiments of the present invention, the one ormore programs determine buffer reclaim limits for the unpredictablejournals every temporal period (e.g., every hour), as a function of theaverage predicted buffer usage and the standard deviation from thepredicted buffer usage. The average predicted buffer usage and thestandard deviation from the predicted buffer usage may comprise theabbreviated set of usage statistics determined by the one or moreprograms (e.g., FIG. 2, 244). Returning to Journal A, as depicted inFIG. 3A, for the unpredictable hour of 05:00-06:00 the average is 7 andthe standard deviation (σ) is 2. The buffer reclaim limit is 7+6*2,calculated using the average +6*σ. Thus, in this example, the allocatedbuffer less 7+6*2 is available for the one or more programs to reclaimfrom Journal A, at the relevant temporal period, which in this case, isat a given hour.

Returning to FIG. 2, the one or more programs determine if the totalavailable buffer size is sufficient to meet the anticipated requirementsof all the journals, for each period of the temporal periods (270).Based on determining that the total available buffer size isinsufficient, the one or more programs may notify the Administrator (anindividual or a program) to provision (manually or automatically) moreshared storage space for all the journals (280).

Based on determining a buffer space requirement for each journal foreach period, the one or more programs allocate buffer space (e.g., fromshared space) to each journal for a temporal period similar to anhistorical temporal period, to which the ranking being relied upon arerelevant (290). Because the one or more programs can associatehistorical temporal periods with current periods (e.g., based on acommonality of season, time of day, time of month, etc.), the one ormore programs can allocate buffer space based both upon a perceivedpredictability of buffer space usage in a given journal for a giventemporal period, as well as based on a perceived unpredictability ofbuffer space usage.

As illustrated in workflow 400 of FIG. 4, although one or more programsin embodiments of the present invention guard against breaches ofthreshold limits by anticipating and continuously adjusting andreadjusting buffer sizes of journals (e.g., FIG. 2, 260), embodiments ofthe present invention include contingencies in case an assigned bufferlimit is breached by an (unanticipated) event. In embodiments of thepresent invention, the one or more programs obtain an event that willbreach the assigned buffer threshold (410) and determine bufferrequirements based on the event. For example, as illustrated in FIG. 4,if the event originated from a predictable journal, the one or moreprograms mark that journal as unpredictable for the current temporalperiod. The one or more programs determine an additional bufferrequirement for this journal until the end of the temporal period, basedon the rate of change of actual buffer usage. The one or more programsdetermine the buffer space to release from the rest of the unpredictablejournals, based on actual buffer usage, buffer reclaim limits, averagepredicted buffer usage, and standard deviation from predicted bufferusage. The one or more programs re-compute the buffer-size thresholdsettings and the buffer reclaim limits for the unpredictable journals,based on the new reallocation plans.

Referring to FIG. 4, the one or more programs redistribute buffer spaceto the journals based on the determined predictability, the additionalspace requirements precipitated by the event, and the portion of theallocated buffer space that can be reclaimed (420). The one or moreprograms update the buffer settings for the journals based on the newbuffer size values (430). If the threshold event originated from apredictable journal, the one or more programs designate this journal asunpredictable in the current temporal period (i.e., time window) (440).

As aforementioned, the one or more programs can define the dynamicthreshold to detect an SLA breach, for all the journals, based onhistorical trends, and periodically update this threshold. Thus, when athreshold-based event is raised by a journal, the one or more programsmay analyze the actual buffer usage trend (in the current time window)of the journal, to estimate the additional buffer-size required for thejournal (based on rate of change).

In some embodiments of the present invention, one or more programs mayreclaim buffer space for a journal experiencing a threshold event froman unpredictable journal. In an aspect of some embodiments of thepresent invention, the one or more programs analyze the actual usage ofall the unpredictable journals and compare the actual usage with thecorresponding predicted usage (roughly predicted based on historicaldata) to reclaim some buffer space. For example, the buffer sizereclaimed from the unpredictable journals is proportional to its actualusage, predicted usage, and predicted standard deviation (based onhistorical data).

FIG. 5 is a workflow 500 depicting certain aspects of some embodimentsof the present invention precipitated, as in FIG. 4, by the receipt ofan event that will breach an assigned buffer threshold. Upon receipt ofthe event (510), the one or more programs analyze the buffer-sizerequirements of the journals sharing the shared space, which includesdetermining a total available buffer space for reallocation by summingthe buffer reclaim limits for all the unpredictable journals sharing thespace (520). The one or more programs determine the total buffer spacerequirement, until the next temporal period commences, by summing thebuffer space requirements, for the journals, with threshold events, thatoccurred before this point time (530). Based on determining that thetotal available buffer space is less than the total buffer spacerequirement for all the unpredictable journals, the one or more programsnotify an administrator about the potential gap in total-buffer-space(540). The one or more programs may also request additional shared spaceto mitigate the anticipated issue.

As illustrated in workflow 600 of FIG. 6, some of the journals areunpredictable, and others may become unpredictable, which canpotentially complicate the ability of the one or more programs toanticipate, reliably, buffer space requirements. Thus, in someembodiments of the present invention, the one or more programs maydetermine that a given journal has become unpredictable and is operatingbeyond the allocated buffer space limits (610), resulting in highercentral processing unit (CPU) resource utilization (with someperformance degradation). The one or more programs may respond to thisbehavior utilizing the approach illustrated in FIG. 6. Based ondetermining that a given journal has become unpredictable and isoperating beyond the allocated buffer space limits, the one or moreprograms either compress or decompress data stores in the given journal(620) resulting in higher central processing unit (CPU) resourceutilization (with some possible performance degradation). The one ormore programs may also blacklist the consumer and/or producer of thejournal (630), to block the source of the problematic behavior. One ormore programs may also notify a messaging system administrator of theissue with the journal.

A given journal has become unpredictable and is operating beyond theallocated buffer space limits can be understood as a “rouge” journal. Inembodiments of the present invention, one or more programs canautomatically detect rouge journals. A journal becomes a rouge journalwhen a producer continuously generates data at a very high rate(compared to rate of consumption), such that the buffer consumptionincreases continuously. The effects of rogue journals on the messagingsystem can be mitigated because the one or more programs in embodimentsof the present invention repeatedly (and continuously) re-plan andre-distribute the allocated buffers of the unpredictable journals.

FIG. 7 is a workflow 700 of some embodiments of the present inventionthat illustrates how the one or more programs mitigate the potentialeffects of one or more rogue journals on the functionality of themessaging system. In order to avoid these issues, the one or moreprograms identify journals as being problematic and reject content thatwould potentially stretch buffer limits within these journals. In someembodiments of the present invention, the one or more programs obtain athreshold breach event during a temporal period (710). Based onreceiving the threshold breach event, the one or more programsre-allocate buffer size distributions for the journals based on thepredictabilities of the journals (720). To re-allocate the buffer sizedistributions, the one or more programs determine additional bufferspace requirements for each journal for the temporal period, based onthe rate of change of actual buffer usage (722). The one or moreprograms track a number of times each journal has required an increasein its buffer space requirement (724). The one or more programsdetermine if the number of times increases in buffer space have beenrequired exceed a predetermined tolerance threshold (725). In someembodiments of the present invention, this threshold is three (3). Basedon the adjustments for a journal exceeding the threshold, the one ormore programs mark the journal as being rouge (726). Based onidentifying a journal as rogue, the one or more programs switch on avalue of a data compression flag in a register (e.g., set the flag totrue) and based on this flag being on, the one or more programs compressmessages stored in the journal decompress the messages on retrieval(727). The one or more programs notify an administrator (e.g., aprogram) of those journals marked as rouge (730).

In some embodiments of the present invention, the one or more programsmay utilize two different thresholds in order to determine how to handlea potentially rogue journal. While violating a lower threshold may causethe one or more programs to identify the journal as rogue (726) andcompress the associated data (727), should the one or more programsdetermine that the number of times increases in buffer space have beenrequired exceed a higher predetermined tolerance threshold, the one ormore programs may take further actions in order to prevent theproblematic journal from creating issues within the messaging system. Inan embodiment of the present invention, when the one or more programsdetermine that the number of times increases in buffer space have beenrequired exceed a second predetermined tolerance threshold (728), wherethe second threshold exceeds the initial threshold, the one or moreprograms, and the one or more programs previously identified the journalas rogue, the one or more programs reject all further incoming messagesdestined for the journal (729). In an embodiment of the presentinvention, the initial threshold is three (3), while the secondthreshold is six (6).

Because the one or more programs consistently evaluate previousallocations and journal sizes, a journal that the one or more programsdetermined to be rogue can be re-classified. In an embodiment of thepresent invention, the one or more programs monitor all rogue journalsat regular intervals. These regular intervals may be smaller than thetemporal periods. For example, when a temporal period is an hour, thisinterval may be thirty (30) minutes or fifteen (15) minutes. Duringthese checks, if the one or more programs determine that rate of changeof actual buffer usage is negative, and the actual buffer usage is lessthan the buffer size threshold, the one or more programs remove therouge designation from the journal and turn off the data compressiontag.

Embodiments of the present invention include a computer-implementedmethod, a computer program product, and a computer system that includeone or more programs that obtain historical data related to buffer spaceusage for each journal in a group of journals comprising a messagingsystem, wherein each journal utilizes buffer space comprising a commonshared storage resource, by monitoring activity in each journal overrepeating temporal periods. The one or more programs determine, for eachjournal, based on the obtained historical data, a predictability foreach journal for each monitored period of the repeating temporalperiods, where the predictability is selected from the group consistingof: predictable and unpredictable, where a predictable journal, for amonitored period, uses a predictable amount of buffer space during themonitored period, and an unpredictable journal, for the monitoredperiod, uses an unpredictable amount of buffer space during themonitored period. The one or more programs generate, based on thehistorical data, usage statics for each journal during each monitoredperiod, where the usage statistics generated for each monitored periodare dependent on whether the journal was predictable or unpredictableduring the monitored period. For each monitored period, the one or moreprograms rank predictable journals for the monitored period, by a bufferspace requirement for each journal of the predictable journals. Based onthe rankings for a given monitored period, the one or more programsdetermine a buffer space requirement for each journal of the group ofjournals for a current period, where the current period shares one ormore temporal qualities with the given monitored period. Based on thisdetermination, the one or more programs allocate, for use during thecurrent period, based on the buffer space requirement for each journal,buffer space to each journal of the group of j ournals, from the bufferspace in the common shared storage resource.

In some embodiments of the present invention, the one or more programsdetermine the buffer space requirement for each journal of the group ofj ournals for the current period by determining a buffer size thresholdfor each journal based on the predictability of each journal for thegiven monitored period. The one or more programs also determine aportion of the buffer space in the common shared storage resourceallocated to one or more journals of the predictable journals in thegiven monitored period, available to reclaim for allocating to one ormore journals of the unpredictable journals in the given monitoredperiod, the use during the current period; and set a buffer size and athreshold buffer size for each journal.

In some embodiments of the present invention, in advance of or during asecond period, the one or more programs obtain an event related to oneor more journals. The one or more programs determine that the event thatwill breach the threshold buffer size of the one or more journals of thegroup of journals during the second period. The one or more programsdetermine additional buffer space requirements for the one or morejournals, based on the event. The one or more programs alsoautomatically reallocate a portion of buffer space in the common sharedstorage resource to the one or more journals, based on predictability ofthe one or more journals during a second monitored period, wherein thesecond monitored period and the second period share one or more commontemporal qualities, the additional space requirements, and the portionof the buffer space available to reclaim.

In some embodiments of the present invention, the one or more programsdesignate the one or more journals previously determined to bepredictable for the second monitored periods as unpredictable for thesecond monitored period.

In some embodiments of the present invention, in reallocating theportion of buffer space, the one or more programs determine anadditional buffer space requirement for each journal for the secondperiod, based on the rate of change of actual buffer usage of eachjournal.

In some embodiments of the present invention, the one or more programsmonitor a number of times the one or more processors automaticallyre-allocate buffer space to each of the one or more journals, based onobtaining events related to the one or more journals. Based on thenumber exceeding a first threshold, the one or more programs designatethe one or more journals as rogue. The one or more programs compressmessages stored in the one or more journals. In some embodiments of thepresent invention, based on the number exceeding a second threshold, theone or more programs reject all further incoming messages destined forthe one or more journals. The second threshold may exceed the firstthreshold.

In some embodiments of the present invention, the one or more programsnotify an administrator that the one or more journals were designatedrogue.

In some embodiments of the present invention, the one or more programsgenerate the usage statics for each journal during each monitored periodfor a predictable journal by determining, for predictable journals inthe group of journals, a minimum usage, a maximum usage, an averageusage, and a standard deviation and for unpredictable journals in thegroup of journals, an average predicted buffer usage and a standarddeviation from the average predicted buffer usage.

In some embodiments of the present invention, the one or more programsallocate buffer space to each journal of the group of journals bydetermining a combined buffer space requirement for the group ofjournals. The one or more programs also determine that buffer spacecomprising the common shared storage resource is less than combinedbuffer space requirement. The one or more programs also notify anadministrator to provision additional shared storage space for themessaging system.

In some embodiments of the present invention, based on the rankings fora second given monitored period, for a period subsequent to the currentperiod, the one or more programs determine an updated buffer spacerequirement for each journal of the group of journals for the periodsubsequent to the current period, wherein the period subsequent to thecurrent period shares one or more temporal qualities with the secondgiven monitored period. Based on the determining, the one or moreprograms adjust, for use during the a period subsequent to the currentperiod, based on the updated buffer space requirement for each journal,the buffer space allocated to each journal of the group of journals,from the buffer space in the common shared storage resource.

Referring now to FIG. 8, a schematic of an example of a computing node,which can be a cloud computing node 10. Cloud computing node 10 is onlyone example of a suitable cloud computing node and is not intended tosuggest any limitation as to the scope of use or functionality ofembodiments of the invention described herein. Regardless, cloudcomputing node 10 is capable of being implemented and/or performing anyof the functionality set forth hereinabove. In an embodiment of thepresent invention, the producers 120 a-120 c (FIG. 1), the consumers 150a-150 b (FIG. 1) and the shared disk storage 110 can all be understoodas part of a cloud computing node 10 (FIG. 8) and if not a portion of acloud computing node 10, then one or more general computing node thatincludes aspects of the cloud computing node 10.

In cloud computing node 10 there is a computer system/server 12, whichis operational with numerous other general purpose or special purposecomputing system environments or configurations. Examples of well-knowncomputing systems, environments, and/or configurations that may besuitable for use with computer system/server 12 include, but are notlimited to, personal computer systems, server computer systems, thinclients, thick clients, handheld or laptop devices, multiprocessorsystems, microprocessor-based systems, set top boxes, programmableconsumer electronics, network PCs, minicomputer systems, mainframecomputer systems, and distributed cloud computing environments thatinclude any of the above systems or devices, and the like.

Computer system/server 12 may be described in the general context ofcomputer system-executable instructions, such as program modules, beingexecuted by a computer system. Generally, program modules may includeroutines, programs, objects, components, logic, data structures, and soon that perform particular tasks or implement particular abstract datatypes. Computer system/server 12 may be practiced in distributed cloudcomputing environments where tasks are performed by remote processingdevices that are linked through a communications network. In adistributed cloud computing environment, program modules may be locatedin both local and remote computer system storage media including memorystorage devices.

As shown in FIG. 8, computer system/server 12 that can be utilized ascloud computing node 10 is shown in the form of a general-purposecomputing device. The components of computer system/server 12 mayinclude, but are not limited to, one or more processors or processingunits 16, a system memory 28, and a bus 18 that couples various systemcomponents including system memory 28 to processor 16.

Bus 18 represents one or more of any of several types of bus structures,including a memory bus or memory controller, a peripheral bus, anaccelerated graphics port, and a processor or local bus using any of avariety of bus architectures. By way of example, and not limitation,such architectures include Industry Standard Architecture (ISA) bus,Micro Channel Architecture (MCA) bus, Enhanced ISA (EISA) bus, VideoElectronics Standards Association (VESA) local bus, and PeripheralComponent Interconnect (PCI) bus.

Computer system/server 12 typically includes a variety of computersystem readable media. Such media may be any available media that isaccessible by computer system/server 12, and it includes both volatileand non-volatile media, removable and non-removable media.

System memory 28 can include computer system readable media in the formof volatile memory, such as random access memory (RAM) 30 and/or cachememory 32. Computer system/server 12 may further include otherremovable/non-removable, volatile/non-volatile computer system storagemedia. By way of example only, storage system 34 can be provided forreading from and writing to a non-removable, non-volatile magnetic media(not shown and typically called a “hard drive”). Although not shown, amagnetic disk drive for reading from and writing to a removable,non-volatile magnetic disk (e.g., a “floppy disk”), and an optical diskdrive for reading from or writing to a removable, non-volatile opticaldisk such as a CD-ROM, DVD-ROM or other optical media can be provided.In such instances, each can be connected to bus 18 by one or more datamedia interfaces. As will be further depicted and described below,memory 28 may include at least one program product having a set (e.g.,at least one) of program modules that are configured to carry out thefunctions of embodiments of the invention.

Program/utility 40, having a set (at least one) of program modules 42,may be stored in memory 28 by way of example, and not limitation, aswell as an operating system, one or more application programs, otherprogram modules, and program data. Each of the operating system, one ormore application programs, other program modules, and program data orsome combination thereof, may include an implementation of a networkingenvironment. Program modules 42 generally carry out the functions and/ormethodologies of embodiments of the invention as described herein.

Computer system/server 12 may also communicate with one or more externaldevices 14 such as a keyboard, a pointing device, a display 24, etc.;one or more devices that enable a user to interact with computersystem/server 12; and/or any devices (e.g., network card, modem, etc.)that enable computer system/server 12 to communicate with one or moreother computing devices. Such communication can occur via Input/Output(I/O) interfaces 22. Still yet, computer system/server 12 cancommunicate with one or more networks such as a local area network(LAN), a general wide area network (WAN), and/or a public network (e.g.,the Internet) via network adapter 20. As depicted, network adapter 20communicates with the other components of computer system/server 12 viabus 18. It should be understood that although not shown, other hardwareand/or software components could be used in conjunction with computersystem/server 12. Examples include, but are not limited to: microcode,device drivers, redundant processing units, external disk drive arrays,RAID systems, tape drives, and data archival storage systems, etc.

It is to be understood that although this disclosure includes a detaileddescription on cloud computing, implementation of the teachings recitedherein are not limited to a cloud computing environment. Rather,embodiments of the present invention are capable of being implemented inconjunction with any other type of computing environment now known orlater developed.

Cloud computing is a model of service delivery for enabling convenient,on-demand network access to a shared pool of configurable computingresources (e.g., networks, network bandwidth, servers, processing,memory, storage, applications, virtual machines, and services) that canbe rapidly provisioned and released with minimal management effort orinteraction with a provider of the service. This cloud model may includeat least five characteristics, at least three service models, and atleast four deployment models.

Characteristics are as Follows:

On-demand self-service: a cloud consumer can unilaterally provisioncomputing capabilities, such as server time and network storage, asneeded automatically without requiring human interaction with theservice's provider.

Broad network access: capabilities are available over a network andaccessed through standard mechanisms that promote use by heterogeneousthin or thick client platforms (e.g., mobile phones, laptops, and PDAs).Resource pooling: the provider's computing resources are pooled to servemultiple consumers using a multi-tenant model, with different physicaland virtual resources dynamically assigned and reassigned according todemand. There is a sense of location independence in that the consumergenerally has no control or knowledge over the exact location of theprovided resources but may be able to specify location at a higher levelof abstraction (e.g., country, state, or datacenter). Rapid elasticity:capabilities can be rapidly and elastically provisioned, in some casesautomatically, to quickly scale out and rapidly released to quicklyscale in. To the consumer, the capabilities available for provisioningoften appear to be unlimited and can be purchased in any quantity at anytime.

Measured service: cloud systems automatically control and optimizeresource use by leveraging a metering capability at some level ofabstraction appropriate to the type of service (e.g., storage,processing, bandwidth, and active user accounts). Resource usage can bemonitored, controlled, and reported, providing transparency for both theprovider and consumer of the utilized service.

Service Models are as Follows:

Software as a Service (SaaS): the capability provided to the consumer isto use the provider's applications running on a cloud infrastructure.The applications are accessible from various client devices through athin client interface such as a web browser (e.g., web-based e-mail).The consumer does not manage or control the underlying cloudinfrastructure including network, servers, operating systems, storage,or even individual application capabilities, with the possible exceptionof limited user specific application configuration settings.

Platform as a Service (PaaS): the capability provided to the consumer isto deploy onto the cloud infrastructure consumer-created or acquiredapplications created using programming languages and tools supported bythe provider. The consumer does not manage or control the underlyingcloud infrastructure including networks, servers, operating systems, orstorage, but has control over the deployed applications and possiblyapplication hosting environment configurations.

Infrastructure as a Service (IaaS): the capability provided to theconsumer is to provision processing, storage, networks, and otherfundamental computing resources where the consumer is able to deploy andrun arbitrary software, which can include operating systems andapplications. The consumer does not manage or control the underlyingcloud infrastructure but has control over operating systems, storage,deployed applications, and possibly limited control of select networkingcomponents (e.g., host firewalls).

Deployment Models are as Follows:

Private cloud: the cloud infrastructure is operated solely for anorganization. It may be managed by the organization or a third party andmay exist on-premises or off premises.

Community cloud: the cloud infrastructure is shared by severalorganizations and supports a specific community that has shared concerns(e.g., mission, security requirements, policy, and complianceconsiderations). It may be managed by the organizations or a third partyand may exist on-premises or off-premises.

Public cloud: the cloud infrastructure is made available to the generalpublic or a large industry group and is owned by an organization sellingcloud services.

Hybrid cloud: the cloud infrastructure is a composition of two or moreclouds (private, community, or public) that remain unique entities butare bound together by standardized or proprietary technology thatenables data and application portability (e.g., cloud bursting forload-balancing between clouds).

A cloud computing environment is service oriented with a focus onstatelessness, low coupling, modularity, and semantic interoperability.At the heart of cloud computing is an infrastructure that includes anetwork of interconnected nodes.

Referring now to FIG. 9, illustrative cloud computing environment 50 isdepicted. As shown, cloud computing environment 50 includes one or morecloud computing nodes 10 with which local computing devices used bycloud consumers, such as, for example, personal digital assistant (PDA)or cellular telephone 54A, desktop computer 54B, laptop computer 54C,and/or automobile computer system 54N may communicate. Nodes 10 maycommunicate with one another. They may be grouped (not shown) physicallyor virtually, in one or more networks, such as Private, Community,Public, or Hybrid clouds as described hereinabove, or a combinationthereof. This allows cloud computing environment 50 to offerinfrastructure, platforms and/or software as services for which a cloudconsumer does not need to maintain resources on a local computingdevice. It is understood that the types of computing devices 54A-N shownin FIG. 9 are intended to be illustrative only and that computing nodes10 and cloud computing environment 50 can communicate with any type ofcomputerized device over any type of network and/or network addressableconnection (e.g., using a web browser).

Referring now to FIG. 10, a set of functional abstraction layersprovided by cloud computing environment 50 (FIG. 9) is shown. It shouldbe understood in advance that the components, layers, and functionsshown in FIG. 10 are intended to be illustrative only and embodiments ofthe invention are not limited thereto. As depicted, the following layersand corresponding functions are provided:

Hardware and software layer 60 includes hardware and softwarecomponents. Examples of hardware components include: mainframes 61; RISC(Reduced Instruction Set Computer) architecture based servers 62;servers 63; blade servers 64; storage devices 65; and networks andnetworking components 66. In some embodiments, software componentsinclude network application server software 67 and database software 68.

Virtualization layer 70 provides an abstraction layer from which thefollowing examples of virtual entities may be provided: virtual servers71; virtual storage 72; virtual networks 73, including virtual privatenetworks; virtual applications and operating systems 74; and virtualclients 75.

In one example, management layer 80 may provide the functions describedbelow. Resource provisioning 81 provides dynamic procurement ofcomputing resources and other resources that are utilized to performtasks within the cloud computing environment. Metering and Pricing 82provide cost tracking as resources are utilized within the cloudcomputing environment, and billing or invoicing for consumption of theseresources. In one example, these resources may include applicationsoftware licenses. Security provides identity verification for cloudconsumers and tasks, as well as protection for data and other resources.User portal 83 provides access to the cloud computing environment forconsumers and system administrators. Service level management 84provides cloud computing resource allocation and management such thatrequired service levels are met. Service Level Agreement (SLA) planningand fulfillment 85 provide pre-arrangement for, and procurement of,cloud computing resources for which a future requirement is anticipatedin accordance with an SLA.

Workloads layer 90 provides examples of functionality for which thecloud computing environment may be utilized. Examples of workloads andfunctions which may be provided from this layer include: mapping andnavigation 91; software development and lifecycle management 92; virtualclassroom education delivery 93; data analytics processing 94;transaction processing 95; and allocating shared buffer space 96.

The present invention may be a system, a method, and/or a computerprogram product at any possible technical detail level of integration.The computer program product may include a computer readable storagemedium (or media) having computer readable program instructions thereonfor causing a processor to carry out aspects of the present invention.

The computer readable storage medium can be a tangible device that canretain and store instructions for use by an instruction executiondevice. The computer readable storage medium may be, for example, but isnot limited to, an electronic storage device, a magnetic storage device,an optical storage device, an electromagnetic storage device, asemiconductor storage device, or any suitable combination of theforegoing. A non-exhaustive list of more specific examples of thecomputer readable storage medium includes the following: a portablecomputer diskette, a hard disk, a random access memory (RAM), aread-only memory (ROM), an erasable programmable read-only memory (EPROMor Flash memory), a static random access memory (SRAM), a portablecompact disc read-only memory (CD-ROM), a digital versatile disk (DVD),a memory stick, a floppy disk, a mechanically encoded device such aspunch-cards or raised structures in a groove having instructionsrecorded thereon, and any suitable combination of the foregoing. Acomputer readable storage medium, as used herein, is not to be construedas being transitory signals per se, such as radio waves or other freelypropagating electromagnetic waves, electromagnetic waves propagatingthrough a waveguide or other transmission media (e.g., light pulsespassing through a fiber-optic cable), or electrical signals transmittedthrough a wire.

Computer readable program instructions described herein can bedownloaded to respective computing/processing devices from a computerreadable storage medium or to an external computer or external storagedevice via a network, for example, the Internet, a local area network, awide area network and/or a wireless network. The network may comprisecopper transmission cables, optical transmission fibers, wirelesstransmission, routers, firewalls, switches, gateway computers and/oredge servers. A network adapter card or network interface in eachcomputing/processing device receives computer readable programinstructions from the network and forwards the computer readable programinstructions for storage in a computer readable storage medium withinthe respective computing/processing device.

Computer readable program instructions for carrying out operations ofthe present invention may be assembler instructions,instruction-set-architecture (ISA) instructions, machine instructions,machine dependent instructions, microcode, firmware instructions,state-setting data, configuration data for integrated circuitry, oreither source code or object code written in any combination of one ormore programming languages, including an object oriented programminglanguage such as Smalltalk, C++, or the like, and procedural programminglanguages, such as the “C” programming language or similar programminglanguages. The computer readable program instructions may executeentirely on the user's computer, partly on the user's computer, as astand-alone software package, partly on the user's computer and partlyon a remote computer or entirely on the remote computer or server. Inthe latter scenario, the remote computer may be connected to the user'scomputer through any type of network, including a local area network(LAN) or a wide area network (WAN), or the connection may be made to anexternal computer (for example, through the Internet using an InternetService Provider). In some embodiments, electronic circuitry including,for example, programmable logic circuitry, field-programmable gatearrays (FPGA), or programmable logic arrays (PLA) may execute thecomputer readable program instructions by utilizing state information ofthe computer readable program instructions to personalize the electroniccircuitry, in order to perform aspects of the present invention.

Aspects of the present invention are described herein with reference toflowchart illustrations and/or block diagrams of methods, apparatus(systems), and computer program products according to embodiments of theinvention. It will be understood that each block of the flowchartillustrations and/or block diagrams, and combinations of blocks in theflowchart illustrations and/or block diagrams, can be implemented bycomputer readable program instructions.

These computer readable program instructions may be provided to aprocessor of a general purpose computer, special purpose computer, orother programmable data processing apparatus to produce a machine, suchthat the instructions, which execute via the processor of the computeror other programmable data processing apparatus, create means forimplementing the functions/acts specified in the flowchart and/or blockdiagram block or blocks. These computer readable program instructionsmay also be stored in a computer readable storage medium that can directa computer, a programmable data processing apparatus, and/or otherdevices to function in a particular manner, such that the computerreadable storage medium having instructions stored therein comprises anarticle of manufacture including instructions which implement aspects ofthe function/act specified in the flowchart and/or block diagram blockor blocks.

The computer readable program instructions may also be loaded onto acomputer, other programmable data processing apparatus, or other deviceto cause a series of operational steps to be performed on the computer,other programmable apparatus or other device to produce a computerimplemented process, such that the instructions which execute on thecomputer, other programmable apparatus, or other device implement thefunctions/acts specified in the flowchart and/or block diagram block orblocks.

The flowchart and block diagrams in the Figures illustrate thearchitecture, functionality, and operation of possible implementationsof systems, methods, and computer program products according to variousembodiments of the present invention. In this regard, each block in theflowchart or block diagrams may represent a module, segment, or portionof instructions, which comprises one or more executable instructions forimplementing the specified logical function(s). In some alternativeimplementations, the functions noted in the blocks may occur out of theorder noted in the Figures. For example, two blocks shown in successionmay, in fact, be executed substantially concurrently, or the blocks maysometimes be executed in the reverse order, depending upon thefunctionality involved. It will also be noted that each block of theblock diagrams and/or flowchart illustration, and combinations of blocksin the block diagrams and/or flowchart illustration, can be implementedby special purpose hardware-based systems that perform the specifiedfunctions or acts or carry out combinations of special purpose hardwareand computer instructions.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting. As used herein, thesingular forms “a”, “an” and “the” are intended to include the pluralforms as well, unless the context clearly indicates otherwise. It willbe further understood that the terms “comprises” and/or “comprising”,when used in this specification, specify the presence of statedfeatures, integers, steps, operations, elements, and/or components, butdo not preclude the presence or addition of one or more other features,integers, steps, operations, elements, components and/or groups thereof.

The corresponding structures, materials, acts, and equivalents of allmeans or step plus function elements in the claims below, if any, areintended to include any structure, material, or act for performing thefunction in combination with other claimed elements as specificallyclaimed. The description of one or more embodiments has been presentedfor purposes of illustration and description, but is not intended to beexhaustive or limited to in the form disclosed. Many modifications andvariations will be apparent to those of ordinary skill in the art. Theembodiment was chosen and described in order to best explain variousaspects and the practical application, and to enable others of ordinaryskill in the art to understand various embodiments with variousmodifications as are suited to the particular use contemplated.

What is claimed is:
 1. A computer-implemented method, comprising:obtaining, by one or more processors, historical data related to bufferspace usage for each journal in a group of journals comprising amessaging system, wherein each journal utilizes buffer space comprisinga common shared storage resource, by monitoring activity in each journalover repeating temporal periods; determining, by the one or moreprocessors, for each journal, based on the obtained historical data, apredictability for each journal for each monitored period of therepeating temporal periods, wherein the predictability is selected fromthe group consisting of: predictable and unpredictable, wherein apredictable journal, for a monitored period, uses a predictable amountof buffer space during the monitored period, and an unpredictablejournal, for the monitored period, uses an unpredictable amount ofbuffer space during the monitored period; generating, by the one or moreprocessors, based on the historical data, usage statics for each journalduring each monitored period, wherein the usage statistics generated foreach monitored period are dependent on whether the journal waspredictable or unpredictable during the monitored period; for eachmonitored period, ranking, by the one or more processors, predictablejournals for the monitored period, by a buffer space requirement foreach journal of the predictable journals; based on the rankings for agiven monitored period, determining, by the one or more processors, abuffer space requirement for each journal of the group of j ournals fora current period, wherein the current period shares one or more temporalqualities with the given monitored period; and based on the determining,allocating, by the one or more processors, for use during the currentperiod, based on the buffer space requirement for each journal, bufferspace to each journal of the group of journals, from the buffer space inthe common shared storage resource.
 2. The computer-implemented methodof claim 1, wherein determining the buffer space requirement for eachjournal of the group of j ournals for the current period comprises:determining, by the one or more processors, a buffer size threshold foreach journal based on the predictability of each journal for the givenmonitored period; determining, by the one or more processors, a portionof the buffer space in the common shared storage resource allocated toone or more journals of the predictable journals in the given monitoredperiod, available to reclaim for allocating to one or more journals ofthe unpredictable journals in the given monitored period, the use duringthe current period; and setting, by the one or more processors, a buffersize and a threshold buffer size for each journal.
 3. Thecomputer-implemented method of claim 2, further comprising: in advanceof or during a second period, obtaining, by the one or more processors,an event related to one or more journals; determining, by the one ormore processors, that the event that will breach the threshold buffersize of the one or more journals of the group of journals during thesecond period; determining, by the one or more processors, additionalbuffer space requirements for the one or more journals, based on theevent; and automatically re-allocating, by the one or more processors, aportion of buffer space in the common shared storage resource to the oneor more journals, based on predictability of the one or more journalsduring a second monitored period, wherein the second monitored periodand the second period share one or more common temporal qualities, theadditional space requirements, and the portion of the buffer spaceavailable to reclaim.
 4. The computer-related method of claim 4, furthercomprising: designating, by the one or more programs, the one or morejournals previously determined to be predictable for the secondmonitored periods as unpredictable for the second monitored period. 5.The computer-implemented method of claim 3, wherein automaticallyre-allocating the portion of buffer space further comprises:determining, by the one or more processors, an additional buffer spacerequirement for each journal for the second period, based on the rate ofchange of actual buffer usage of each journal.
 6. Thecomputer-implemented method of claim 3, further comprising: monitoring,by the one or more processors, a number of times the one or moreprocessors automatically re-allocate buffer space to each of the one ormore journals, based on obtaining events related to the one or morejournals; based on the number exceeding a first threshold, designating,by the one or more processors, the one or more journals as rogue; andcompressing, by the one or more processors, messages stored in the oneor more journals.
 7. The computer-implemented method of claim 6, furthercomprising: based on the number exceeding a second threshold, rejecting,by the one or more processors, all further incoming messages destinedfor the one or more journals.
 8. The computer-implemented method ofclaim 7, wherein the second threshold exceeds the first threshold. 9.The computer-implemented method of claim 8, further comprising:notifying, by the one or more processors, an administrator that the oneor more journals were designated rogue.
 10. The computer-implementedmethod of claim 1, wherein generating the usage statics for each journalduring each monitored period for a predictable journal comprises:determining, by the one or more processors, for predictable journals inthe group of journals, a minimum usage, a maximum usage, an averageusage, and a standard deviation and for unpredictable journals in thegroup of journals, an average predicted buffer usage and a standarddeviation from the average predicted buffer usage.
 11. Thecomputer-implemented method of claim 1, wherein allocating buffer spaceto each journal of the group of journals further comprises: determining,by the one or more processors, a combined buffer space requirement forthe group of journals; determining, by the one or more processors, thatbuffer space comprising the common shared storage resource is less thancombined buffer space requirement; and notifying, by the one or moreprocessors, an administrator to provision additional shared storagespace for the messaging system.
 12. The computer-implemented method ofclaim 1, further comprising: based on the rankings for a second givenmonitored period, for a period subsequent to the current period,determining, by the one or more processors, an updated buffer spacerequirement for each journal of the group of journals for the periodsubsequent to the current period, wherein the period subsequent to thecurrent period shares one or more temporal qualities with the secondgiven monitored period; and based on the determining, adjusting, by theone or more processors, for use during the a period subsequent to thecurrent period, based on the updated buffer space requirement for eachjournal, the buffer space allocated to each journal of the group ofjournals, from the buffer space in the common shared storage resource.